4 replies to this topic

[Stiggytoo]

Looking for some clear-cut answers regarding various volumes in my new 1014cc engine. There are some knowledgeable people on here who I know will know - if you know what I mean... 

 

1) Approximately how much does a 0.010" skim affect the chamber volume of a 12G940. (Alternatively what measurement will result in a 1cc difference) I've read that 12 thou is roughly 1cc. 

2) Does anyone have an idea of the ring land volume I should expect. I am using County 21964 pistons if that helps. 

3) Does the following look correct. 

 

SV=253.5cc

________________

21.4cc - Head 

3.9cc - Payen BK450 H/gasket 

1.66cc - Deck height 0.5mm 

1cc - Pocket 

0.7cc? - Ring lands 

 

I got a CR of 9.845:1.

I'm aiming for around 10.5:1; so according to the information I have, I should be looking at a 19.4cc head.

 

Any help appreciated. 

[Cooperman]

Put 19.4 cc into a combustion chamber with the head sitting upside down and completely level.

Then see how far below the deck level the fluid is and that is the amount to have machined off.

 

I think, form memory, that each 0.010" skimmed from a standard head educes the volume by 0.75 cc, but you do need to measure it as above really.

I hope this helps.

[Stiggytoo]

Thanks Cooperman.

[ACDodd]

What cam and rockers are you using?

AC

[Stiggytoo]

Mg metro cam with standard A+ rockers at the moment.